New technology has been reported for the synthesis of olefins from methanol. (Chemical Engineering, January 1996, p. 17.) As described in the literature, this process converts methanol in a fluidized-bed reactor at a pressure between 1 and 5 atmospheres and a temperature in the range of 350° C. to 500° C. A zeolite-type catalyst consisting of silicon-aluminum-phosphorous oxide is used to promote the reaction.
The process is capable of converting at best about 80 percent of the methanol to ethylene and propylene in varying proportions of these olefins. With methanol selling as a premium over hydrocarbon feed-stocks, the relatively low yield of products is a drawback. Furthermore, the process is disadvantaged by the fact that heterogeneous catalysts generally undergo deactivation during usage.
Therefore, it is an object of the present invention to offer an improved method for the manufacture of olefins. This object, as well as other features and advantages, will be apparent from the following description and the figure that is included.
Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.